Magnet cores are manufactured in many different ways. British Patent Specification 563517 teaches a method in which a strip is wound around a cylinder, whereafter the cylinder then is removed and the coiled strip then is compressed. A yoke is formed by winding another strip to a rectangular shape, whereafter the compressed coil is inserted into the yoke. Sintered or punched cores and yokes are examples of other variants. The evenness of the transition areas between the magnetic elements varies markedly, and these areas must therefore be ground or polished to small tolerances at subsequent high costs. Toroidally wound strip is another available alternative, although with limited use and requiring a complicated winding procedure.